Apparatus for the reproduction of sf



A. MARE.

APPARATUS FOR THE REPRODUCTION OF S JND. APPLICATION FILED Now. Is. 1917.

Patentedl m. 23,1919.

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ALEX ANDER MARE, OF LONGSIGI-I'l, ENGLAND.

APPARATUS FOR THE REPRODUCTION OF SOUND.

eaters, I

Specification of Letters Patent.

Patented Dec, 23, I219.

Application filed November 13, 1917. Serial No. 201,728.

To all whom it may concern Be it known that I, ALEXANDER ltlnnn, a subject of the King of Great Britain and Ireland, and a resident of IJongsight, Manchester, in the county of Lancaster, England, have invented certain new and useful Improvements in or Relating to Apparatus for the Reproduction of Sound, of which the following is a specification.

This invention relates to apparatus for the reproduction of'sounds, particularly to telephone receivers, and has special reference to the ordinary flat or disk diaphragm which is clamped around or near its periphery.

According to the invention, the parts between which an ordinary flat or disk diaphragm is clamped around or near to. its periphery are formed so that two or more pairs of narrow or knife-edge like surfaces result between which the diaphragm is clamped.

In the accompanying drawing, Figure 1 is a part sectional view of a telephone receiver illustrating one embodiment of the invention and Figs. 2, 3, 4 and 5 are similar views of modifications thereof.

Iteferring first to Figs. 1 and 2, the ends 7 of the receiver body a and cap or ear-piece b are grooved or otherwise formed so that two pair of narrow or knife edge-likesurfaces a 5 and a 6 result between which the diaphragm c is clamped on the screwing u) of the cap or ear-piece Z). When the c amping means are each merely provided with a single circular knife-like edge, and

these edges should not accurately oppose one another, distortion of the diaphragm would result which would materially impair the sound-producing efficiency of the instrument. By means of two or more concentric knife edge-like surfaces, such distortion of the diaphragm 0 is guarded against and the surface engaged is not materially increased.

Instead of the clamping surfaces 5 if, being formed on the cap or ear-piece b as in Figs. 1 and 2, they may, as shown in Ifig. 3, he formed on a ring 5 fitted in the"cap or car-piece, and, if necessary, a rlng d of metal, ebonite, fiber or other suitable material may be fitted'conveniently on a ledge on the ring I), as shown, to adjust the size of the air space. Preferably, however, the ring b is of triangular or beveled section with its outer periphery parallel to its axis and its inner periphery inclined, as illustrated in Fig, st, and the cap or ear-piece 7) is provided with a correspondingly shaped groove in which the ring I) fits and the clamping surfaces 6 b on the latter are cemented or otherwise appropriately attached to the diaphragm 0, so that the screwiug up of the cap or ear-piece not only securely clamps the diaphragm, but also accurately centers same with respect to the magnet c.

In the embodiment illustrated in Fig. 5, the body 6 is fashioned with three concentric knife-edge like surfaces 6 b and b and the body a with a like number of compleinentary surfaces (6 a and a so that the diaphragm is clamped between three pair of knife-edged surfaces, viz :-a 6 ,486 and It will be seen that in all cases the diaphragm is clamped circumferentially at two or more points spaced radially, one point of clamping being at or near the periphery of the diaphragm and the other or others at a little distance therefrom and from each other, and .between these points; the diaphragm is unclamped. Such manner of clamping the diaphragm considerably reduces the damping due to clamping and permits the diaphragm to attain a greater amplitude of vibration with greater efiiciency in sound reproduction than when it is clamped as ordinarily over a comparatively large radial area.

What I claim as my invention and desire to secure by'Iietters Patent is:-

1. In apparatus for the, reproduction of sound, a vibrating diaphragm, and a plurality of pairs-of opposed knife-edge like clamping surfaces directly in engagement with, and between which said diaphragm is clamped circumferentially at a plurality of radially-spaced points.

2. In apparatus for the reproduction of sound, a body, a sup aort on said body,-a clamping member, a p urality of concentric narrow or knife-edge like clamping surfaces on said support, a plurality of concentric knife-edge like clamping surfaces on saidclamping member arranged opposite to those on said support, and a vibrating dia phragm directly in engagement with and clamped between said pluralitiesiof clamping surfaces.

8. In apparatus for the reproduction of sound, a body, asupporton said body, a on said ring opposite to those on said supplurality of knife-edge like clamping surport, and a vibrating diaphragm clamped faces on said body, a cap on said body, a between said pluralities of clamping sur- 10 beveled-ring in said cap, a correspondingly faces and secured to those on said ring.

5 beveled surface on said cap against which In witness whereof I have'hereunto set the beveled face of said ring bears, a plumy hand I rality of narrow or knife-edge like surfaces ALEXANDER MARR. 

